This is directed to a troffer-style light fixture using cross-lighting. In particular, this is directed to using LED lights to cross-light the internal surface of a troffer and mix light.
One of the most prolific commercial light fixtures is a fluorescent troffer fixture. This fixture includes a troffer forming a housing into which one or more fluorescent light tubes are inserted. The troffer includes a base surface from which side walls extend to form an open box. The fixture can include ballast (e.g., a power supply) for maintaining a desired orientation of the fixture when it is fixed to a surface (e.g., a ceiling). The fixture can include one or more acrylic lenses, diffusers or parabolic louvers for controlling the light emitted by the fluorescent tubes. Because fluorescent tubes emit omnidirectional light (e.g., in 360 degrees), the interior surface of the troffer fixture can include a reflector for redirecting up light (e.g., light emitted towards the fixture) down towards the environment.
To increase the power efficiency of light fixtures, some fluorescent light tubes have been replaced with LED devices. In particular, because the luminous efficacy of LED devices has increased, LEDs have become viable light sources for commercial applications. Contrary to a fluorescent light tube, however, a LED device is not omni-directional but instead may only emit light in no more than a 180 degree cone. This means that a LED based troffer will emit light down and out of the troffer, and therefore does not require a reflector along the top inner surface of the troffer. To soften the emitted light, and optimize the light for the fixture and the space where it is installed, the fixture can include one or more lenses, reflectors, diffusers and additional optics.
LED-based troffer light fixtures have some limitations, however. In particular, the luminous efficacy of LEDs can be less than that of fluorescent light tubes. For example, the luminous efficacy of LEDs can be less than 80 lumens per watt, while the luminous efficacy of fluorescent light tubes can be 100 lumens per watt. In addition, the quality of the light emitted by a LED may differ from that emitted by a fluorescent light tube. For example, a fluorescent light tube can include a powdered phosphor coating that can create a soft light. In contrast, a LED package provides a point light source that can be inherently harsher and can increase the glare profile of the fixture. To soften the harshness of LED light, diffusers with low transmission properties can be used, but such diffusers would compromise the efficiency of the fixture and eliminate the advantage of using LED-based troffer fixtures instead of fluorescent light tube-based troffer fixtures. Different approaches for LED-based troffer fixtures may be desirable to provide a better lighting experience